1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', 'bs5a6dhnu2ve9bv0odjg9kfcr2', '216.73.216.220', '1764094366', '1764094366', '/shop_content.php?XTCsid=3f98699a7205aa16d7f8014dc7c0d34a&coID=4')

[XT SQL Error]